Treatment of Thrombotic Thrombocytopenic Purpura Using Solvent Detergent Treated Plasma.

Background: Patients with Thrombotic Thrombocytopenic Purpura require immediate therapy with large volumes of plasma. They have been reported to respond well to plasma exchange (PE) with FFP (78%) 1 and CSP (95%) 2 . We initiated a randomized prospective trial with CSP and solvent detergent treated plasma (SDP) intended to show non inferiority. Methods: Patients were randomized to receive either of the exchange fluids at 1.5 PV x 3 days then 1 PV x 4–6 days. Laboratory values were followed with ADAMTS-13 levels measured according to Furlan 3 . The primary end point was survival at 6 months. Results: A total of 62 of the required 280 patients entered the study then the supply of SDP was discontinued. 3/35 patients receiving CSP and 1/27 on SDP died before 1 month. These values are not significant but the study is underpowered so statistical analysis is not possible. FVIII and vWF levels were elevated in all patients at entry. 34/50 patients tested also had antibodies to CD36. 9 patients had no ADAMTS-3 at entry, 19 had between 5–50%, 9 patients had 50–100% and 15/62 patients tested had normal levels. Inhibitors were present at between 5–50% levels in 22/50 patients tested whereas 9 patients had complete inhibition of ADAMTS-13 and 18 had normal enzyme activity. Conclusions: Patients with TTP appear to respond well to SDP thereby offering a relatively safer therapeutic option for PE. An insufficient number of patients were entered to achieve statistical significance. Both the ADAMTS-13 and the inhibitor levels show great variation and are not prognostic.